Balancing machine



D. KILGOUR BALANCINGl MACHINE May 1, 1923.

2 sheets-sheet 1 Filed Feb. 4, 1920 A TTORNEYS.

Patented May 1, L1923.L

' Wwe el f "DAVID KILGOUE, or WILKINSBUR'G, PENNSYLVANIA, AssIGNoR lro wEsTINGIIioUsEJ ELECTRIC & :wIANUEAcrUaINGf` COMPANY, A conPoEA'rIoN or PEnuvsrLvANIA.l -j

' BALANCING MACHINE.

Application led February 4,1920. Serial No. 356,342.

To all 107mm t may concer/n.: Be vit known that I, DAVID KILGouR, citizen of the United States, and a resident of'v Wilkinsburg, in the county o f Allegheny' andv State of Pennsylvania, liave madev a new and useful Invention in Balancing Machines, of which the following isa specification. l

This invention Vrelates to balancing machines and` particularly to machines adapted to be employed in ascertaining the welght distribution with relation to the axis of rotation of the body to be balanced. I

Methods usually employed lfor obtaining static balance of rotatable bodies are not always accurate andmay not disclose thefact that the gravity axis of the body Vdoes not coincide -with the axis about which it is lto be rotated. For example, the distribution of weight about the axis'of rotation may not be symmetrical longitudinally or transversely of the axis, but itA may be such that an improper distribution will not bev disclosed by tests for static balance. The present methods Vof static balancing may not disclosea weight'distribution in which the heavy spots are not in the sameA transverse plane, whereas' rotation of the body will introduce a new and disturbing force. That is, the heavy sp'ots are now subjected to centrifugal force, which of course acts radially, and as they are not in the same transverse plane', with lrelation to the axis of rotation, a-couple is produced and vibration results.

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the couple must be elimlnated or counterbalanced, and it is necessary to find the intensity and direction of the resultantr forces, or their equivalent, which occasion the couple, in orderthat kthey may .be compensated, as for example, by introducing counterbalancing forces or couples. Obviously, if the "disturbing forcesl are completely counterbalanced, the body will be in dynamic A further object is to produce a new andl improved dynamic balancing machine in,

which the opposite ends of the body to be In order to dynamically balance kthe bodyI investigated are mounted in sucha manner that the, weight distribution longitudinally of the axis ofrotationv maybe ascertained with sui'cient accuracy to perfectthe dynamic balance ofthe body. ff

A furthero'bject is to produce'a new and improved dynamic balancing `machine `and la new and improved methody of 'investigat-l ing dynamic balance tating bodies. A further object is to produce a-'new and' improved dynamic balancing machine which" or unbalance of 1ro-- may be employed for accurately determining the condition of dynamic/balance orvunbalance of a body without the necessity of first statically balancing the body.

A further ob'ect is to `produce new an vimproved and" adjusting and controllingv mechanisms for balancing machines.

A further object is to produce a new and improved pedestal for-'balancing machines.v

These and otherobjects which will "be made apparent throughout the further descriptionl of -my invention are vattained Vby means'of apparatus-embodying the features herein described and'illus'trated in the drawings accompanying and forming a `|`part hereof. kIn the drawingsf'Fig. l is a diagrammatic sectional'view of a balancingy machiney embodying'myinvention@ v Fig. 2'is a diagrammatic sectional view lalong the line 2-2'of Fig. 1. f Fig. 3 is a sectional detail view of a portion of the weight shifting mechanism.

In Figs, 1 and 2 I' have illustrated a5 balancing machine having a suitable-base 5y and a pedestal 7 which, as shown, lis slid# ably mounted kon the base 5 and is?` adapted to support orpartally vsupportthe body to be investigated for dynamic balance. As` illustrated, one end of a turbine rotor 8 is mountedin the balancing machine in po--' sition to be investigated.

The rotor 8 may be rotated in any suitable manner, for example by means of aU flexible shaft 9, V operated from any suitable i power source, for example, the motor 4.

As illustrated, thev pedestal 7 is provided with a spherically seated bearing 12 inv which one end 'of the shaft of the rotor 8 is journaled. -As shown, the pedestal 7 is supported .on an `Ibeam 15, which extends longitudinally of the rotor and is suicientlyl flexible through its web portion to per-V mit the upper endsy of the pedestal to vibrate in a lateral plane, i. e., in a plane substantially at right angles to the aXis of the rotor. As shown, the pedestal 7 is enclosed within a suitable housing 17. which does not interfere with the vibratory motion of the pedestal, and which encloses the working parts of the pedestal. The pedestal may be moved along the base 5 so as to accommodate rotors or other bodies of different lengths. Vhile the housing 17 is likewise movable along the base it is adapted to be rigidly secured in place on the base, by means of bolts 17a.

The vibrations or lateral movements of the upper end of the pedestal 7 may be limited by means of adjusting stops 18 mounted on the rigid housing 17. One stop is shown on each side of the pedestal. As shown, both stops 18 are adapted to be simultaneously operated by a shaft 19,4

which extends across the housing 17 and is geared to the stops in such a manner that a movement of one stop is accompanied by an. equal `and opposite movement of the other stop. I have also shown adjustable springs 2O mounted in the housing 17 and bearing against the opposite side of the pedestal 7 for the purpose of either damping or accentuating the vibration of the pedestal. As illustrated, the force of the springs may be adjusted by means of suitable screws 21which vI have shown provided with hand wheels 21a. As illustrated, the screws v21 kare mounted in caps 22 which may be removed for the purpose of changing the springs.

I have illustrated means associated with the pedestal 7 for counteracting the unbalanced forces or couples set up by the rotation of the rotor 8 during thevoperation of testingy it for dynamic balance. This means includes a rotatable wheel or disc 23 mounted on the pedestal 7 and adapted to be rotated about an axis parallel to the'axis of rotation of the rotor 8.l An adjustable weight 24 is mounted on thedisc 23, the weight being' carried by a screw25l so that it is capable of being rmoved radially toward and away from the center of rotation of the disc. e

VIn Fig. 3, I -have shown an enlarged view of a device suitable for adjusting lthe position of the weight 24 irrespective of whether the disc 23 is or is not rotating. As illustrated. the screw 25 terminates within the hollow interior of the hub of the disc and is provided at its inner end with a bevel gear 26 which is adapted to mesh with two other bevel gears 27 and 23. The bevel gears 27 and 28 are shown axially aligned with the axis of rotation of the disc 23 and meshing with opposite sides of the gear 26. As illustrated. the gear 27 is mounted on a shaft 29 which extends through 1 -hollow shaft 30 on which the gear 28 is mounted. Both shafts 29 and 30 are, of course, aligned with the axis of rotation of the disc 23 and are respectively provided with hand wheels 31 and 32. As shown in Fig, 1, the hand wheels 31 and 32 are located in an easily accessible position outside of the pedestal housing 17, so that the radial position of the weight 24, with relation to the disc 23, may be easily adjusted. lhen the disc y23 is at rest either hand wheel 31 or 32 may be employed for shifting the position of the weight 24 in either direction. However, when the disc 23 is rotating, the screw 25 may be turned in one direction by holding the hand wheel 31 against rotation, and in the other direction by holding the hand wheel 32 against rotation. Thus the weight 24 may be moved outwardly with relation to the center of the disc ,by holding one hand wheel. and it may be moved inwardly by holding the other hand wheel. It will be apparent that with the arrangement of the gears 25, 26 and 27 hillustrated .both hand wheels 31 .and '32 will normally `tend to rotate with the disc 23, and that the adjustment of the weight 24, above described, may be accomplished by manually As illustrated, the disc 23 is mounted on a shaft 34, which is supported in lsuitable bearings mounted on the pedestal 7 and on which I have shown a spiral or helical gear 35. Below and parallel with the shaftl 34, I have shown another shaft 36 which, as illustrated, is adapted'to be driven by `.a lay shaft 37 through the agency of sprocket wheels 38 yand a chain 39. Feathered on the -shaft 36, I have showna spiral or helical gear 40 which meshes with the gear 35 and therefore drives the `disc 23. As shown, thegear 40 may be rmoved along theshaft 36 by means of a shifter 41. The Ashifter 41 is adapted lto engage opposite sides ,of the gear 40 and shown as mounted on two rods 42 and 42a slidably mounted below `and in parallel relation with the shafts 34 and 36. At an intermediate point the shifter 41 is engaged by a threadedshaft 413s() that it may be shifted .-to different .longitudinal positions by merely turning the shaft. A hand wheel 43 is shown* on lthe outer end of the shaft 41a .for this purpose, anda worm driven pointer 44 and scale 45 indi- Il i) nasale/i4l Cates the angular position of the gear 40 with relation to the gear 35.` l y The lay shaft 37 Vis preferably driven lat such a speed, relative to the' speed of the rotor 8, that the rotor and the adjustable Weight 2li operate in synchronism, that is, at the same speed. The angular relation between the rotor and the weight may be varied by means of tli-e mechanism employed for shifting the longitudinal position of the gear 40. For example, the Weight 24' may be shifted to a leading or lagging angular position relative to the rotor 8 by turning the hand Wheel 48 so as to shift the gear 40 With relation to the gear 35 and thereby cause an angular advance or lag of the disc 23, and hence the Weight 24,' This results from the angular disposition of the teeth of the gears 40 and 35. It Will, of course be understood that ivith the apparatus illustrated, the rotation or" the rotor and the Weight 24 is not synchronous during the short time the angular position of the Weight is being altered.

In operation, the rotor 8 to be investigated for dynamic balance is first mounted in the machine and connected to suitable driving means by the iiexible shaft 9. The adjustable Weight 24 is preferably in-its intermediate or counterbalanced position. The motor 4: is then started causing the rotor and the Weight to rotate in synohronism. The stops 18 are then moved away from the pedestal and if the rotor is out of balancethe pedestal will start to vibrate. rlhe vibrations may be damped or accentuated by properly adjusting the springs 20. y

In order to correct an unbalanced condition of the rotor, it is necessary to determine the angular position and the intensity of the disturbing forces or couples or of the resultant of the forces or couples. rhis is accomplished by shifting `the position of the Weight 24 both in angular and' in radial directions, as necessary, until the vibrations of the pedestal or pedestals are'reduced to a minimum or are substantially eliminated. This operation introduces counterbalancing forces or couples and results in a dynamic balance of the rotating parts of the balancing machine, including the rotor 8 as a part of the machine. It also definitely indicates the changes in Weight distribution of the rotor 8 necessary to accomplish its dynamic balance. It is apparent that the apparatus indicates the intensity and direction of the disturbing forces or couples, since the ra dial position of each Weight Q4- ivith relation to its disc may be readily ascertained and the angular position of each Weight With relation to the rotor 8 may also be ascertained b v means of the pointer 44, The hand Wheels 3l and 32 may be provided With cooperating scales to indicate the radial position of the Weight 24 associated with them.

r. VIn practicek the ,usuali` procedure'isi to 'pro-ii 'i vide two'pedestals and to asv nearly as lpos'- sible eliminate the vibrations of one pedestal f or the vibrations occasioned by oneend iof the rotor. vThe other endv .of 'the rotor' is vtlienbalanced as near asfposible. lliejlat-A j ter operation usually introduces nevv forces? which disturb the'balanc'e ofthe previously balancedend. The 'end first balancedv is re'-Y balanced until the vibrations 'of the' sup-v porting pedestal are reduced to a minimum andthe operation is repeated, if necessary, until a satisfactory balance ishobtaine'd at' both ends ofthe machine. Material'isthen added to orremoved from' dilferent portions'l of the rotor, so as tol accomplish the neces-v` sary distribution of Weight inthe rotor to place it in dynamic balance.` After thero' torhas-been corrected, thelvvei'ghts 24 are' again moved to their intermediate or` coun-v vv ter-balanced positions, and the balancing op'- eration is repeated for the purpose ofV ensuring correct balancing of the rotor.

While l have described and illustrated vbut one embodiment of my invention, it Will be apparent to those skilled in thev art that y various changes, modifications, additions and omissions may be made in., the apparaff` tus described and illustrated. Without departing from the spiritand scope of the inven-Y tion, as set forth by the appended claims.

`What l claim is:

. ln combination. in a balancing machine,

a movable support-on which the body .to be balanced is yrotatively mounted, means for rotating said body, a rotatable Weight asso-V ioo x ciated With said support and means for rotating said Weight in synchronism With ,said

body including a pair ofv intermeshing. gears having inclined teeth,fand means for moving one of said gears longitudinally With relation to the other vto cause said Weight to lead or lag with respect to said bodyduring the period of operation of said means r and While the body andk Weighty are in motion.

to be balanced isrotatively-mounted, means for rotating` `said bodys a rotatable Weightv l 2. ln combination in a balancing mar chine, a` movable support on Which the body body during the; period off operation of said" means and While the body and Weight are in motion. and means" for 'indicating' the angular displacement of said Weight with relation to said body.

3. in' a balancing machine, asu'pport for the body to be balanced and capable of vibrating in response to unbalanced forces eX- erted bythe body when rotated, a vrrevolvable Weight associated with said support, means for revolvingV the Weight, a screw for varying the radius at which the Weight revolves, a gear on the end of said screw near the center of revolution, gears meshing on opposite sides ot' said gear and mounted with theiraxes coinciding` with the axis of revolution and means for turning said last mentioned gears.

et. In a balancing machine, the combina tion oft' a pedestal member, a bearing' carried by the pedestal member for a body to be balanced, a counterbalancing device carried by the pedestal member, flexible supporting means for the pedestal member, means forv rotating the body and the counterbalancing device in synchronism, said counterloalaneing,` device including mass means which may be adjusted radially or circumferentially, and means for adjusting the mass means While the body and the counterbalancing device are in motion.'

In a balancing machine, the combination of supporting means for a. body to be balanced, rotatable counter-balancing means, a source ot power, transmission means between thev source of power and the body and the counterbalancing device, the transmission means for the counterbalancing device includingg` meshing' .gears having` inclined teeth, means for shitting one oi said gears in one direction or the other to cause said counterbalancing device to lead or lag with relation to'said body, and indicating means operated by the shifting means' to indicate the extent of lead or lag.

In testimony whereof, I have hereunto subscribed my name this 31st day of December, 1919.

DAVID KLGOUR. 

